Rocking bolster wagon



Sept. 12,. 196 J. o. BRADFORD ROCKING BOLSTER WAGON Filed March 15, 1965m R0 0F X TD 2 NA 2 E? X VB N 4 0 Z N H X m w 6 4 w 0Q 64 d m m 2 3 ND X3 M. H 2

Patented Sept. 12, 1967 3,341,216 ROCKING BOLSTER WAGON John 0.Bradford, 1015 N. Lott Blvd,

Gibson City, Ill. 60936 Filed Mar. 15, 1965, Ser. No. 439,541 4 Claims.(Cl. 2806.11)

This invention relates to a rocking bolster wagon or other type offour-wheeled vehicle wherein a non-rocking bolster is provided for therear wheels and a rocking bolster is provided for the front or steerablewheels.

One object of the invention is to provide a rocking bolster wherein therocking of the bolster shifts the point of contact between the bolsterand the axle toward the same side that the center of gravity of the loadin the Wagon is displaced when travelling over uneven ground. This helpsto prevent tipping and stabilizes the loaded wagon, and is particularlyimportant in gravity wagons which necessarily have a high center ofgravity.

Another object is to provide a comparatively simple rocking bolsterstructure wherein a bolster supporting member has a substantially planarsupporting surface and a bolster member has a rocker element adapted torock on such supporting surface, means being provided for confining thebolster member against endwise movement relative to the supportingmember.

Still another object is to provide such means to prevent endwisemovement in the form of a link having opposite ends pivoted to thesupporting member and the bolster member.

A further object is to provide a double link arrangement wherein twolinks cooperate with each other to also prevent upward movement of thebolster member away from the supporting member, thereby retaining therocker element of the bolster member in substantial contact with therocker supporting surface at all times, the two links for this purposeextending in opposite directions from the ends of the bolster membertoward the center of the supporting member.

Still a further object is to provide a relationship between thecurvature of the rocker element, the length of the link and a curvedpath described by a pivot point of the link on the bolster member whenit is free to rock on the supporting member, the radius of the linkbeing equal to the radius of such curvature and the pivot point of thelink to the supporting member coinciding with the center for suchcurvature.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various parts of myrocking bolster wagon, whereby the objects above contemplated areattained, as hereinafter more fully set forth, pointed out in my claimsand illustrated in detail on the accompanying drawing, wherein:

FIG. 1 is a front elevation of a gravity wagon with my rocking bolsterconstruction applied thereto; a

FIG. 2 is a line diagram illustrating the geometry of my bolsterconstruction and showing it in the level position;

FIG. 3 is a similar line diagram showing the front axleof the wagontipped as on an inclined surface; and

FIG. 4 is an enlarged end view of the rocking bolster construction shownin FIG. 1.

On the accompanying drawing I have used the reference numeral toindicate the upper rectangular box portion of a gravity wagon, 12 thesloping front wall thereof, 14 the sloping rear wall thereof and 16 thesloping bottom wall thereof. These walls terminate adjacent a flowcontrol door or sliding gate 18 which can be opened for permitting grainand similar commodities in the wagon body 10, 12, 14, 16 to flow bygravity into a suitable container such as a bushel basket or the like.

Due to the geometry of a gravity wagon its center of gravity isrelatively high. As illustrated in FIG. 1 it may be mounted at its frontend on an axle 20 of the steerable type having Wheels 22. The mountingdisclosed comprises a bolster member 24 and a bolster supporting member26. The member 26 has a web 28 providing a substantially planarsupporting surface for a rocker element 30, secured to the lower surfaceof the bolster member 24. As shown in FIG. 5, the rocker element 30 isin the form of a pair of curved shoes, and the entire construction maybe formed of steel welded together in an obvious manner. Uprights 25extend from the bolster member 24 to the wagon box and can also be ofwelded construction. Usually there are reinforcing frame members which Iomit from the disclosure in FIG. 1 because they form no part of mypresent invention.

The steerable axle 20 is at the front of the wagon box, and at the rearthere is a suitable non-rocking bolster 24 uprights 25 non-steering axle20 and wheels 22 shown in FIG. 1 by breaking away the correspondingparts 24, 25 and 22.

To complete my rocking bolster construction, I provide a front link 32and a back link 34. These links have outer ends pivoted at A and B tothe bolster member 24 and adjacent inner ends pivoted at C and D to thebolster supporting member 26. The relationship of the curvature of therocker element 30, the length of the links 32 and 34 and the positionsof the pivots A, B, C and D are quite important in my rocking bolsterconstruction as will now be described in detail.

Referring first to FIGS. 2 and 3, the lower curved surface of the rockerelement 30 is shown as a curved line 30X. The curvature 30X has a radiusR. The pivot points A and C are connected by the link 32 which is hererepresented by radius r.

The bolster 24 is shown in central or level position in FIG. '2, and canrock to limits indicated 24X and 24Y in FIGS. 2 and 3. The surface ofthe web 28 on which' the curvature 30X rocks is indicated at 28X and thetangent point between the two at T and T, respectively.

Assume now that the curvature 30X is free to rock on the surface 28X. Itcan rock to the limits dictated at 24X and 24Y. As it does this, thepoint A will describe an arcshaped curvature 36 to the limits A and A"to which the radii r and r" correspond. If the center for the curvature36 is explored, it will be found to occur at point C (where the threeradii r, r and r" cross each other) and, accordingly, the length of r isalso thus found. Therefore, if the link 32 from pivot A to pivot C ismade equal to the length r the link will confine the bolster member 24against endwise movement relative to the surface 28X except as dictatedby a free rocking of the curvature 30X of the surface 28X, and therewill at no time be any tendency to either lengthen or shorten the linkthus avoiding any undue strain on the link or wear on its pivots.

The link 34 is a duplicate of the link 32 in the opposite direction and,accordingly, it likewise does not cause any endwise shifting of thebolster member 24 except as dictated by the rocking of 30X on 28X. Thetwo links 32 and 34 cooperate to perform the additional function ofpreventing any upward movement of the bolster member 24 and thereby therocker element 30 away from the web 28 of the rocker supporting member26.

FIG. 2 shows a complete diagram including lines 22X 3 has likewiseshifted to the right a slightly greater distance d. This helps toprevent tipping and effects greater stabilization of the loaded wagon.It is thus obvious that the rocking arrangement disclosed producesimproved results from the standpoint of better control of the load asthe wagon travels over uneven ground.

From the foregoing specification it Will be obvious that I have provideda comparatively simple rocker and linkage arrangement wherein the linksprevent undesirable endwise movement of the bolster member relative tothe bolster supporting member and also upward movement of the bolstermember away from the bolster supporting member, yet at the same timepermit smooth rocking action. At the same time, the linkage is soselected relative to the radius R in FIGS. 2 and 3 that free rockingmovement of the rocker element on the surface 28X results thuseliminating any sliding action and, accordingly, wear as between thetwo, and results in substantially no strain on the pivots A, B, C and Ddue to the relationship of parts as disclosed. Obviously, the radius Rcan be increased or decreased as desired and the resulting pivot pointsA and C varied accordingly to the resulting arc 36. The resultingstructure consists of merely the bolsterrocker member, its supportingmember, and a pair of links pivoted to the two and serving to act in thecapacity outlined. Relatively simple steel shapes can be used forfabricating the bolster construction and a few simple welds serve torigidly connect the parts together for trouble-free operation and longlife.

The shifting contact or point of tangency of my rocking bolster tends tostay over the point CWG thus removing much of the strain from the frameand body of the wagon. The bolster member rocks uphill at any time thatthe front and rear axles are not in the same plane. The resultingbolster action is especially valuable in a semimonocoque constructionsuch as is generally used in gravity wagons.

Some changes may be made in the construction and arrangement of theparts of my rocking bolster wagon without departing from the real spiritand purpose of my invention, and it is my intention to cover by myclaims any modified forms of structure or use of mechanical equivalentswhich may reasonably be included within their scope.

I claim as my invention:

1. In a rocking bolster wagon, a bolster member, a bolster supportingmember having a substantially planar supporting surface, a rockerelement on said bolter member adapted to rock on said supportingsurface, and means for confining said bolster member against endwisemovement relative to said supporting member comprising a pair ofsubstantially horizontal links, one end of each link being pivoted tosaid supporting member adjacent the outer ends thereof whereby saidlinks extend from opposite ends of said supporting member toward thecenter of said bolster member, and the other end of each link beingpivoted to said bolster member adjacent the center thereof, said linksbeing operable to also prevent upward movement of said bolster memberaway from said supporting member and thereby retain said rocker elementin substantial contact with said supporting surface at all times.

2. In a rocking bolster wagon, a bolster member, a bolster supportingmember having a substantially planar supporting surface, a rockerelement on said bolster member adapted to rock on said supportingsurface, means for confining said supporting member comprising a linkhaving opposite ends thereof pivoted to said supporting member and saidbolster member, the pivot point of said link to said bolster memberdescribing a curved path when said bolster member is free to rock onsaid supporting surface, the radius of said link being equal to theradius of such curvature and the pivot point of said link to saidsupporting member coinciding with the center for such curvature.

3. In a rocking bolster wagon, a bolster member, a bolster supportingmember having a substantially planar supporting surface, a rockerelement on said bolster member adapted to rock on said supportingsurface, means for confining said bolster member against endwisemovement relative to said supporting member comprising a pair of linkshaving opposite ends pivoted to said supporting member and said bolstermember, said links extending from opposite ends of said bolster membertoward the center of said supporting member, said links being operableto also prevent upward movement of said bolster member away from saidsupporting member and thereby retain said rocker element in substantialcontact with said supporting surface at all times, the pivot points ofsaid links to said bolster member describing curved paths when saidbolster member is free to rock on said supporting surface, the radii ofsaid links being equal to the radii of such curvatures and the pivotpoints of said links to said supporting member coinciding with thecenters for such curvatures.

4. In a rocking bolster Wagon, a bolster member, a bolster supportingmember having a substantially planar supporting surface, a rockerelement on said bolster member adapted to rock on said supportingsurface, and means for confining said bolster member against endwisemovement relative to said supporting member comprising a pair ofsubstantially horizontally extending links having outer ends pivoted tosaid bolster member adjacent the ends thereof and inner ends pivoted tosaid supporting member adjacent the center thereof, the radii of saidlinks being so related to the radius of said rocker element, and thepivot points of said links to said supporting member and said bolstermember being so related to said radii that free rocking motion of saidrocker element of said bolster member relative to said supporting memberis had without said links imparting any endwise sliding movement to saidrocker element relative to said planar supporting surface.

References Cited UNITED STATES PATENTS 1,026,851 5/1912 Dearing 2801l21,288,757 12/1918 Quinn 280/112 1,716,233 6/1929 Larsh 2806.l1 1,743,8681/1930 Royer 280ll1 2,032,657 3/ 1936 Frederickson 2801 11 BENJAMINHERSH, Primary Examiner.

M. S. SALES, P. GOODMAN, Assistant Examiners.

1. IN A ROCKING BOLSTER WAGON, A BOLSTER MEMBER, A BOLSTER SUPPORTINGMEMBER HAVING A SUBSTANTIALLY PLANAR SUPPORTING SURFACE, A ROCKERELEMENT ON SAID BOLTER MEMBER ADAPTED TO ROCK ON SAID SUPPORTINGSURFACE, AND MEANS FOR CONFINING SAID BOLSTER MEMBER AGINST ENDWISEMOVEMENT RELATIVE TO SAID SUPPORTING MEMBER COMPRISING A PAIR OFSUBSTANTIALLY HORIZONTAL LINKS, ONE END OF EACH LINK BEING PIVOTED TOSAID SUPPORTING MEMBER ADJACENT THE OUTER ENDS THEREOF WHEREBY SAIDLINKS EXTEND FROM OPPOSIDE ENDS OF SAID SUPPORTING MEMBER TOWARD THECENTER OF SAID BOLSTER MEMBER, AND THE OTHER END OF EACH LINK BEINGPIVOTED TO SAID BOLSTER MEMBER ADJACENT THE CENTER THEREOF, SAID LINKSBEING OPERABLE TO ALSO PREVENT UPWARD MOVEMENT OF SAID BOLSTER MEMBERAWAY FROM SAID SUP-